Abstract: The integral equation is handled using the method of momentes in the complex-frequency domain,the space discretization is fixed for all frequencies and the resulting matrix equation is solved by the conjugate gradient method. The condition of the system matrix is improved in the complex-frequency domain. Good initial estimates are obtained using an extrapolation scheme based on error minimization,thereby the conjugate gradient method converges very fast. The transient response is obtained by carrying out the inverse Laplace transfo rmation by an FFT algorithm. The results of a rectangular cylindrical cavity verify the effectiveness of the new method.

Key words: electromagnetie scattering, conjugate gradient method, transient electromagnetic field, extrapolation